High efficiency AC-polarized arc-discharge lamps, such as metal-halide and medium source rare earth arc-discharge lamps, are quasi-point light sources which provide a high color temperature over a wide power range, especially in the blue color where CCD sensors commonly have a lower spectral responsivity. Generally, such arc-discharge lamps are driven by a periodic signal (e.g., a square wave) to balance the thermal dissipation of the electrodes within the lamp. Unfortunately, when an arc-discharge lamp is utilized as an illumination source in a scanning system, the polarization of the discharge between the electrodes of the lamp causes deleterious line-wise brightness variations on the target being scanned which are transferred to the scanned image. Since the human eye and brain are highly capable of detecting such line-wise brightness variations on the scanned image, arc-discharge Imps have heretofore not been incorporated into scanning systems.